Bin dumper

ABSTRACT

A bin dumper and bin clamp mounted on a vehicle includes a fork lift unit. When moved to the dumping position, the dumping mechanism of the bin dumper tilts the containers in excess of 90* about pivot points adjacent the ends of the tines of the fork lift unit and the clamp mechanism of the bin dumper is activated to positively lock the container to the dumping mechanism during this tilting operation. The empty containers may then be lowered directly onto the ground or the flat bed of a truck, or may be lowered upon a carriage which moves at least several containers into a storage tunnel of the vehicle.

[ Aug. 20, 1974 BIN DUMPER [76] Inventor: Leon R. McRobert, PLO. 760 San Jose, Ocoee, Fla. 95106 [22] Filed: Mar. 30, 1973 [21] Appl. No.: 347,120

Related US. Application Data [62] Division of Ser. No. 228,023, Feb. 22, 1972, Pat. No.

3,595,414 7/1971 Brown ..-214/620 Primary Examiner- -Robert J. Spar Assistant Examiner-Lawrence J. Oresky Attorney, Agent, or Firm-C. E. Tripp 5 7 ABSTRACT A bin dumper and bin clamp mounted on a vehicle includes a fork lift unit. When moved to the dumping position, the dumping mechanism of the bin dumper tilts the containers in excess of 90 about pivot points adjacent the ends of the tines of the fork lift unit and the clamp mechanism of the bin dumper is activated to positively lock the container to the dumping mechanism during this tilting operation. The empty containers may then be lowered directly onto the ground or the flat bed of a truck, or may be lowered upon a carriage which moves at least several containers into a storage tunnel of the vehicle.

6 Claims, 11 Drawing Figures PAIENIEBMIBZOW 3.830.386

MEET 1 IF 7 F'IG 1 PAIENTEB 3.880.386

SHEEI 2 0F 7 PMENTEB M18205!" SNEEI 5 IF 7 T'Il3 El PATENTED NEZOLQH SNEHHI'! 1 BIN DUMPER CROSS REFERENCE TO RELATED APPLICATION This application is a division of my copending US. Pat. application Ser. No. 228,023 for STORAGE VE- HICLE WITH BIN DUMPER, filed on Feb. 22, 1972, now U.S. Pat. No. 3,739,929 which issued on June 19, 1973.

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention pertains to the load handling art and more particularly relates to a mobile vehicle having a container dumping mechanism thereon including a bin supporting clamp mechanism.

2. Description of Prior Art A mobile vehicle having storage capacity for four large containers or bulk bins used for harvesting crops, such as citrus fruit, nuts and prunes is disclosed in US. Fisher Pat. No. 3,561 ,627 which issued on Feb. 9, 1971 and is assigned to the assignee of the present invention. The Fisher apparatus, however, does not include means which will enable the bins to be dumped and must, therefore, relay upon other equipment to perform this dumping function.

Although fork lift vehicles having box dumping mechanisms associated therewith are broadly known in the art as evidenced by U.S. Pat. No. 2,829,789 which issued to Gerhardt et al. on Apr. 8, 1958, such mechanisms are usually rather complicated and expensive and are not associated with a vehicle having bin storage capacity.

SUMMARYOF THE INVENTION The bin dumper of the present invention is mounted on a mobile bin storage vehicle which includes a vertically movable fork lift unit mounted on its forward end which lifts bins from the ground, or from other supporting surfaces, and either stores the bins in a storage tunnel within the vehicle or dumps the products from the bins. When performing the storage operation, the bins are first elevated to a position above the tunnel, a loading carriage is projected forwardly from the floor of the tunnel below the bin, the bin is lowered upon the loading carriage, and the loading carriage is then retracted into the tunnel to position the bin on a roller conveyor floor of the tunnel. Three bins may be picked up from an orchard being harvested and may be loaded directly into the tunnel with at least a fourth bin and preferably a fifth bin stacked on the fourth bin and being carried by the fork lift tines. When handling citrus fruit, each bin conventionally has a 45 inches X 45 inches square base, and may be either about 30 /2 inches or 25 inches tall. It is to be understood, however, that bins of other sizes may be handled by the apparatus.

The loaded vehicle may then be driven out of the orchard to a truck loading depot or the like at which time a discharge ramp at the rear end of the tunnel is pivoted downwardly from a closed position to an open position for discharging the three bins inside the tunnel onto the ground as the vehicle moves forward. These bins are then picked up one at a time by the fork lift unit, are gripped by a bin clamping device of the dumping mechanism, and are dumped into a truck by pivoting the bin in excess of 90 about an axis disposed adjacent the free end of the fork lift tines. The clamping mechanism includes-a bar of U-shaped construction which is pivoted and hydraulically locked against the forward end of the bin in such a way as to lock a rear edge and the floor of the bin firmly against certain surfaces of the dumping mechanism. The clamping device also includes a hold down bar which engages the upper edges of the bins side wall at points adjacent the rear wall.

It is, therefore, one object of the present invention to provide a bin dumper mounted on a mobile vehicle and capable of dumping the product from filled bins into a receiving mechanism while firmly clamping the bin in the dumping mechanism.

Another object is to provide an improved bin gripping and dumping mechanism.

DESCRIPTION OF THE DRAWINGS I the empty bin being lowered onto the loading carriage which is in its extended position supporting the emptied bin.

FIG. 5 is a diagrammatic side elevation with certain parts in section illustrating the loading carriage retracted with the empty bin disposed in the vehicle storage tunnel, with the fork lift tines in position to to-pick up another full bin, and with the discharge ramp pivoted to its open position.

FIG. 6 is an enlarged front end view of the apparatus disclosed in FIG. 1 illustrating the fork lift unit and the dumping mechanism with the bin clamp in its inactive raised position.

FIG. 7 is an enlarged horizontal section taken along lines 7-7 of FIGS. 6 and 8 with certain parts being cut away and with the distance between the fork lift tines being greatly reduced.

FIG. 8 is an enlarged side elevation with parts broken away illustrating the bin dumping mechanism in its lowest position.

FlG.-9 is an enlarged side elevation of a portion of FIG. 8 with parts broken away.

FIG. 10 is a vertical section taken substantially along lines 10l0 of FIG. 6 illustrating the bin clamp in its inactive position in solid lines and in its active clamping position in dotted lines, certain parts of the fork lift unit being cut away.

FIG. 11 is a diagrammatic perspective of a portion of the apparatus illustrated in FIG. 10 but with the dumping mechanism being illustrated in the dumping position.

DESCRIPTION OF THE PREFERRED EMBODIMENT sure of the Fisher patent is incorporated herein by reference.

In general, the storage vehicle and bin dumper 8 comprises a vehicle frame 16 mounted on four wheels 18 certain ones of which are powered and steered by conventional mechanism. The vehicle includes a storage tunnel 20 capable of supporting three containers or bins B, which tunnel is provided with a floor having spaced, freely journaled rollers 21 (FIG. thereon. A loading carriage 22 (FIG. 4) with a raised flange 24 on its forward end is reciprocated by a hydraulic cylinder 26 (FIG. 5) between a retracted position within the tunnel and its extended bin supporting position shown in FIG. 4. When in the extended position, the carriage 22 is disposed between the pair of fork lift tines 28 (FIGS. 6 and 7), and when the carriage 22 is retracted the flange 24 pulls the bin onto the rollers 21 in the storage tunnel 20. When it is desired to remove stored bins B from the tunnel 20, a rear gate 32 (FIG. 5) pivoted at 34 and having a bin supporting surface of free rollers 36 is pivotally lowered from its normal horizontal position by hydraulic cylinders 38.

The fork lift unit 12 (FIGS. 3 and 5-11) comprises a generally vertically extending outer frame 40 of inpins 46.

An inner inverted U-shaped frame 48 includes inner channels 50,52 (FIG. 7) which are slidably received I within the outer frame 40, are connected at their upper ends by a cross bar 54, and are connected intermediate their ends by a center cross bar (not shown). Slide plates 56 are secured to the outer channel members 42 and 44 and guide the inner members 50,52 during their reciprocal movement.

In order to impart reciprocal movement to the inner frame 48, the lower ends of a pair of hydraulic cylinders-57 (FIGS. 3, 7 and 8) are anchored to the outer frame 40 while the upper ends of their piston rods 58 are anchored to the upper end of the inner frame member 48. As best shown in FIGS. 6, 9 and 10, a pair of chains 60 are trained over idler sprockets 62 rotatably mounted on the upper ends fo the inner frame 48. One

end of each chain is anchored to the upper end of the outer frame 40 at 64 (FIG. 9), while the other end of each chain is anchored at 66 to a fork lift tine carrier 68.

The tine carrier 68 (FIG. 3) includes a pair of spaced plates 70 and 72 (FIG. 7) each having a pair of rollers 74 and 76, respectively, journaled thereon and rotatably received in the inner channel members 50,52. The plates 70 and 72 are rigidly connected to vertical legs 78 and 80 (FIGS. 7 and 11) which are connected at their upper ends to a transverse beam 84. Short, inwardly directed beams 86,88 (FIGS. 6 and 7) are connected to the lower ends of the legs 78,80 and have the fork lift tines 28 rigid therewith and projecting forwardly therefrom.

The dumping mechanism 13 (FIGS. 3, 6, 7, 8, 10 and 11) is carried by the fork lift unit 12 and includes a pair of normally vertical side members 102 and 104 which are pivoted from the pick-up position illustrated in FIGS. 6, 7, 8 and 10 to the position illustrated in FIGS. 3 and 1 1 during dumping. Tubular cross bars 105 interconnect the two members 102 and 104 near their upper ends. Short inwardly projecting arms 106 and 108 (FIGS. 6, 7 and 11) are rigidly secured to the lower ends of the side members 102 and 104 and have forwardly extending container supporting bars 109 and 110 rigidly secured to their inner ends and projecting forwardly alongside the associated fork lift tines 28. The forward ends of the bars 109 and 110 are pivotally connected to the fork lift tines 28 adjacent their forward ends by pivot pins 111 and cooperating brackets 112 as best shown in FIGS. 6 and 7. It will be appreciated that the forward edges 113 of the arms 106 and 108 act as bin abutment surfaces to limit the rearward movement of the bins by engaging the rear end of bin side cleats 114 (FIG. 10) secured to the bottom surface of each bin.

Hydraulic cylinders 115 are provided in order to pivot the dumping mechanism 13 from its generally horizontal bin supporting position illustrated in FIGS. 68 and 10 to its bin dumping position as illustrated in FIGS. 3 and 11. The lower end of each cylinder 115 is pivoted to an associated bracket 116 (FIGS. 6, 7, 8 and 11) that is secured to the lower end of the fork lift unit 12. The piston rod 117 of each cylinder 114 has its upper end pivotally connected at 118 to the upper end of the dumping mechanism 13. Rubber bumper brackets 119 (FIGS. 7 and 10) are connected to the side members 102 and 104 and are positioned to engage the legs 78 and 80 ofthe fork lift unit 12 when the dumping mechanism is in its generally horizontal bin supporting position.

An important feature of the invention is the provision of a bin clamp 120 (FIGS. 10 and 11) which firmly holds the bin B in the dumping mechanism 13 during the operation of dumping articles, such as fruit, into a truck T (FIG. 3) or the like without any injury to the bin, and without requiring that the bin-be provided with any special anchoring means.

The bin clamp 120 (FIGS. 6, l0 and 11) comprises a U-shaped bin retainer 122 and a safety bar 123. The bin retainer 122 is pivoted at 124 to intermediate portions of the side members 102 and 104 of the dumping mechanism 13 and includes a bin engaging clamp bar 126 that is adapted to engage the forward surface of the bin. The bin retainer 122 is pivotally connected at 129 to the piston rods 130 of a pair of hydraulic cylinders 132 which are pivotally connected to the upper portion of the dumping mechanism 13. The cylinders 132 are controlled by the vehicles operator to pivot the bin retainer 122 between the inactive vertical position illustrated in solid lines in FIG. 10 to the active bin clamping position illustrated in dotted lines in FIG. 10 and in FIG. 11 wherein a bin B is firmly clamped between the bin supporting surfaces 113 of the arms 106 and 108 and forward clamp bar 126. It will be noted that the clamp bar 126 engages the entire transverse forward side wall of the bin B near its vertical midpoint thus reinforcing this wall during the dumping operation and reducing strain on the bin.

In order to prevent accidental dislodgement of the bin B from the dumping mechanism 13 during the dumping operation, the safety bar 123 is also provided in the bin clamp 120. The safety bar 123 is rigidly connected to a pair of arms 142 pivoted to the bin retainer 122 at pivot points 144. Springs 146 are connected between the arms 142 and the bin retainer 122 and normally hold the safety bar 123 in its inactive position above the bin B as illustrated in solid lines in FIG. 10. However, whenever the bin retainer 122 is moved to its active clamping position illustrated in FIG. 11, the springs 146 are tensioned and force the safety bar 123 into firm engagement with the upper rear edge of the bin thus preventing the bin from inadvertently falling from the dumping mechanism 13.

The operation of the storage vehicle and bin dumper 8 will be described in connection with a harvesting operation and as illustrated in FIGS. 1-5 which illustrate progressive stages of a bin dumping and bin storing operation.

It will first be assumed that a number of filled bins B have been placed on the ground at a loading depot near the truck T to be loaded. During a normal sequence of operations, the operator who has ready access to conventional controls for the vehicle and controls for all hydraulic cylinders, lowers the fork lift unit 12 and drives the vehicle forward to position the fork lift tines 28 under a fruit filled bin B as indicated in FIG. 1. The tilt cylinders 47 may be used to aid the operator in this operation by tilting the fork lift tines 28 within the range of 7 above or 7 below the horizontal.

The operator then activates the lifting cylinders 57 as illustrated in FIG. 2 to raise the bin B to the loading position wherein a bin may be placed upright upon a flat bed truck, or may be dumped into the open topped body of a dump truck T or the like. During this time, the vehicle may be driven toward the truck T (FIG. 3), and at the same time the clamp cylinders 132 are actuated to move the bin retainer 122 (FIGS. 10 and 11) and the safety bar 123 of the bin clamp 120 into their active bin clamping positions illustrated in dotted lines in FIG. 10. When the operator reaches the dumping location, he activates the dumping cylinders 115 thereby pivoting the dumping mechanism 13 through an are slightly in excessof 90 causing the load of fruit in the bin to gravitate into the truck T as illustrated in FIG. 3. The tilt cylinder 47 may also be activated at this time to aid in dumping the fruit therefrom.

It will be noted that the bin clamp bar 126 of the bin clamp 120 provides firm support for the front wall of the bin B during dumping, and that the safety bar 123 prevents accidental dislodgement of the bin B at this time. Also, by causing the bin to be pivoted at the forward end of the tines 28, the operator has little difficulty in judging the dumping height. Since the bin being dumped extends a considerable distance forwardly of the chassis of the vehicle 10 ample space is provided between the vehicle chassis and the truck being loaded thereby minimizing the effort and skills required by the operator. 1

After the product has been dumped from the bin B, the empty bin is returned to its horizontal position, the bin clamp 120 is moved to its inactive raised position, the hydraulic cylinder 26 (FIG. 5) is activated to move the carriage 22 to its extended FIG. 4 position, and the fork lift unit 12 is lowered to place the bin directly upon the carriage 22. The carriage 22 is then retracted moving the empty bin B into the tunnel 20.

The above cycle of operation is repeated until three empty bins B are positioned in the tunnel 20, and one or more empty bins are carried on the extended fork lift tines 28. The vehicle with its load of empty bins B is then driven into the orchard being harvested. The

empty bins are then lowered to the ground at desired locations by activating the hydraulic cylinders 38 (FIG.

5) to lower the gate 32 and allow the empty bins to gravitate to the ground.

The operator then closes the gate 32 and collects three full bins placing them in the tunnel 20 by means of the fork lift unit 12 and carriage 22. If desired, one or two additional full bins may be supported on the fork lift tines 28 before the loaded vehicle is driven out of the orchard to the loading depot. When at the depot, the full bins in the tunnel are lowered onto the ground upon opening of the gate 32 (FIG. 5). If two bins are supported on the fork lift tines 28 they may be lowered directly onto the ground by the lift unit. The fork lift unit is then operated as previously described to pick up and dump each bin in turn.

It will, of course, be understood that the storage vehicle and bin dumper 8 may be used merely as a fork lift unit for loading or unloading bins, pallets, or the like from flat bed trucks.

From the foregoing description it is apparent that the storage vehicle and bin dumper of the present invention incorporates in one vehicle the two functions of storing a plurality of bins or containers for transportation to and from remote areas, and the function of dumping the articles from the containers into any suitable collecting means. The apparatus also includes a simple but unique bin clamping system on the dumping mechanism that provides additional support to the forward load bearing wall thus extending the life of the bins. The upper rear surface of the bin is also engaged during dumping to prevent accidental dislodgement of the bin.

Although the best mode contemplated for carrying out the present invention has been herein shown and described, it will be apparent that modification and variation may be made without departing from what is regarded to be the subject matter of the invention.

What I claim is:

1. An apparatus for dumping articles from containers having front, side and rear walls and a rear abutment surface comprising: a pair of transversely spaced fork lift tines having free ends; tine supporting means including means for raising and lowering said tines between a pick-up position and a dumping position along a generally vertical path; a dumping mechanism carried by said tine supporting means and having a pair of transversely spaced container supporting bars normally disposed in a horizontal plane; means for pivotally connecting said bars on the tines immediately adjacent the free end of said tines; said dumping mechanism including a normally upright frame including upright members secured to the other ends of the supporting bars and having a container abutting surface for engaging the rear abutment surface of the container; container clamping means pivotally mounted on said upright frame about an axis disposed above the upper surface of a container supported on said bars when said bars are in their horizontal positions and including a transversely extending clamp bar; means for pivotally actuating said clamping means for moving said clamping bar between an inactive position spaced from and disposed above the container to an active position engaging the front wall of the container; and means for pivoting said dumping mechanism about the free end of said tines when said clamping mechanism is in its active position to dump articles from the containers; said container clamping means also including a pair of spaced arms for pivotally connecting said clamp bar to said upright frame, and additionally comprising a safety bar pivotally carried by said spaced arms, and resilient means for holding said safety bar spaced from the container when the container is in itsinactive position and for resiliently urging said safety bar against the upper edges of said side walls at a point adjacent said rear wall when said clamping means is moved to its active clamping position.

2. An apparatus for dumping articles from containers having front, side and rear walls and a rear abutment surface comprising: a pair of transversely spaced fork lift tines having free ends; tine supporting means including means for raising and lowering said tines between a pick-up position and a dumping position along a generally vertical path; a dumping mechanism carried by said tine supporting means and having a pair of transversely spaced container supporting bars normally disposed in a horizontal plane; means for pivotally connecting said bars on the tines immediately adjacent the free ends of said tines; said dumping mechanism including a normally upright frame including upright members secured to the other ends of the supporting bars and having a container abutting surface for engaging the rear abutment surface of the container; container clamping means pivotally mounted on said upright frame and including a transversely extending container engaging clamp bar, said clamp bar extending entirely across the front container wall near the vertical midpoint thereof to support said front wall during the dumping operation; means for pivotally actuating said clamping means for moving said clamping bar between an inactive position spaced from and disposed above the container to an active position engaging the front wall of the container; and means for pivoting said dumping mechanism about the free end of said tines when said clamping mechanism is in its active position to dump articles from the containers; said container clamping means also including a pair of spaced arms for pivotally connecting said clamp bar to said upright frame, and additionally comprising a safety bar pivotally carried by said spaced arms, and resilient means for holding said safety bar spaced from the container when the container is in its inactive position and for resiliently urging said safety bar against the upper edges of said walls at a point adjacent said rear wall when said clamping means is moved to its active clamping position.

.3. In a container handling apparatus which includes a mobile vehicle having a vertically movable fork lift unit thereon provided with transversely spaced longitudinally extending fork lift tines and means for raising and lowering said tines: the improvement comprising a container dumping mechanism on sald'fork lift unit; a pair of transversely spaced container supporting bars on said unit normally disposed in a horizontal plane and pivotally connected to the free ends of said tines; a pair of normally vertically extending members connected to the other ends of said bars and transversely spaced apart a greater distance than said container supporting bars and said tines; said vertical members including inwardly directed arms having upright container abutting surfaces adjacent the junction of said vertical arms with said horizontal container supporting bars; generally U- shaped container clamping means connected to said members for pivotal movement about a transverse axis disposed above the upper surface of a container supported on said container supporting bars; means for pivoting said clamping means from a position spaced from the container to a position firmly engaging the wall of the container over which articles are dumped; and means for pivoting said dumping mechanism from said normal position to a dumping position while said clamping means firmly clamps the container against said upright container abutting surfaces; said container clamping means including a pair of spaced arms, and additionally comprising a safety bar pivotally connected to said spaced arms, and resilient means for normally holding said safety bar spaced from and disposed above the container when the container is in its inactive position and for resiliently urging the safety bar against the upper edges of the container side walls when the clamping means is moved to its active container engaging position.

4. An apparatus for dumping articles over a side wall of an open top container which includes a vertically movable fork lift unit with elongated horizontal tines and a rear wall, a dumping mechanism pivotally supported on the tines for supporting the container, and means for selectively pivoting the dumping mechanism from a position supporting the container in an article retaining position to an article dumping position; the improvement which comprises a generally U-shaped container clamping means pivotally mounted on said dumping mechanism and including a transversely extending clamp bar, power means for moving said clamp means between a position spaced from said container and a position engaging and supporting the wall over which articles are dumped when in said dumping position, thus supporting at least part of the weight of said container when in the dumped position and safety means including a transverse bar carried by said clamping means and movable with said clamping means between a position spaced from the container and a position engaging the open top of the container for aiding said clamping bar in maintaining the container in said dumping mechanism during dumping.

5. An apparatus according to claim 4 wherein said dumping mechanism includes a normally horizontal portion and a normally vertical wall, said vertical wall and the rear wall of said fork lift unit each including means defining openings through which containers may be moved for loading containers onto or removing containers from the fork lift unit and the dumping mechanism.

6. An apparatus according to claim 5 wherein the rear wall of the fork lift unit includes means defining container abutment surfaces only adjacent the lower end thereof for allowing movement of the containers through said openings only after the container has been raised a predetermined amount above the fork lift tines. 

1. An apparatus for dumping articles from containers having front, side and rear walls and a rear abutment surface comprising: a pair of transversely spaced fork lift tines having free ends; tine supporting means including means for raising and lowering said tines between a pick-up position and a dumping position along a generally vertical path; a dumping mechanism carried by said tine supporting means and having a pair of transversely spaced container supporting bars normally disposed in a horizontal plane; means for pivotally connecting said bars on the tines immediately adjacent the free end of said tines; said dumping mechanism including a normally upright frame including upright members secured to the other ends of the supporting bars and having a container abutting surface for engaging the rear abutment surface of the container; container clamping means pivotally mounted on said upright frame about an axis disposed above the upper surface of a container supported on said bars when said bars are in their horizontal positions and including a transversely extending clamp bar; means for pivotally actuating said clamping means for moving said clamping bar between an inactive position spaced from and disposed above the container to an active position engaging the front wall of the container; and means for pivoting said dumping mechanism about the free end of said tines when said clamping mechanism is in its active position to dump articles from the containers; said container clamping means also including a pair of spaced arms for pivotally connecting said clamp bar to said upright frame, and additionally comprising a safety bar pivotally carried by said spaced arms, and resilient means for holding said safety bar spaced from the container when the container is in its inactive position and for resiliently urging said safety bar against the upper edges of said side walls at a point adjacent said rear wall when said clamping means is moved to its active clamping position.
 2. An apparatus for dumping articles from containers having front, side and rear walls and a rear abutment surface comprising: a pair of transversely spaced fork lift tines having free ends; tine supporting means including means for raising and lowering said tines between a pick-up position and a dumping position along a generally vertical path; a dumping mechanism carried by said tine supporting means and having a pair of transversely spaced container supporting bars normally disposed in a horizontal plane; means for pivotally connecting said bars on the tines immediately adjacent the free ends of said tines; said dumping mechanism including a normally upright frame including upright members secured to the other ends of the supporting bars and having a container abutting surface for engaging the rear abutment surface of the container; container clamping means pivotally mounted on said upright frame and including a transversely extending container engaging clamp bar, said clamp bar extending entirely across the front container wall near the vertical midpoint thereof to support said front wall during the dumping operation; means for pivotally actuating said clamping means for moving said clamping bar between an inactive position spaced from and disposed above the container to an active position engaging the front wall of the container; and means for pivoting said dumping mechanism about the free end of said tines when said clamping mechanism is in its active position to dump articles from the containers; said container clamping means also including a pair of spaced arms for pivotally connecting said clamp bar to said upright frame, and additionally comprising a safety bar pivotally carried by said spaced arms, and resilient means for holding said safety bar spaced from the container when the container is in its inactive position and for resiliently urging said safety bar against the upper edges of said walls at a point adjacent said rear wall when said clamping means is moved to its active clamping position.
 3. In a container handling apparatus which includes a mobile vehicle having a vertically movaBle fork lift unit thereon provided with transversely spaced longitudinally extending fork lift tines and means for raising and lowering said tines: the improvement comprising a container dumping mechanism on said fork lift unit; a pair of transversely spaced container supporting bars on said unit normally disposed in a horizontal plane and pivotally connected to the free ends of said tines; a pair of normally vertically extending members connected to the other ends of said bars and transversely spaced apart a greater distance than said container supporting bars and said tines; said vertical members including inwardly directed arms having upright container abutting surfaces adjacent the junction of said vertical arms with said horizontal container supporting bars; generally U-shaped container clamping means connected to said members for pivotal movement about a transverse axis disposed above the upper surface of a container supported on said container supporting bars; means for pivoting said clamping means from a position spaced from the container to a position firmly engaging the wall of the container over which articles are dumped; and means for pivoting said dumping mechanism from said normal position to a dumping position while said clamping means firmly clamps the container against said upright container abutting surfaces; said container clamping means including a pair of spaced arms, and additionally comprising a safety bar pivotally connected to said spaced arms, and resilient means for normally holding said safety bar spaced from and disposed above the container when the container is in its inactive position and for resiliently urging the safety bar against the upper edges of the container side walls when the clamping means is moved to its active container engaging position.
 4. An apparatus for dumping articles over a side wall of an open top container which includes a vertically movable fork lift unit with elongated horizontal tines and a rear wall, a dumping mechanism pivotally supported on the tines for supporting the container, and means for selectively pivoting the dumping mechanism from a position supporting the container in an article retaining position to an article dumping position; the improvement which comprises a generally U-shaped container clamping means pivotally mounted on said dumping mechanism and including a transversely extending clamp bar, power means for moving said clamp means between a position spaced from said container and a position engaging and supporting the wall over which articles are dumped when in said dumping position, thus supporting at least part of the weight of said container when in the dumped position and safety means including a transverse bar carried by said clamping means and movable with said clamping means between a position spaced from the container and a position engaging the open top of the container for aiding said clamping bar in maintaining the container in said dumping mechanism during dumping.
 5. An apparatus according to claim 4 wherein said dumping mechanism includes a normally horizontal portion and a normally vertical wall, said vertical wall and the rear wall of said fork lift unit each including means defining openings through which containers may be moved for loading containers onto or removing containers from the fork lift unit and the dumping mechanism.
 6. An apparatus according to claim 5 wherein the rear wall of the fork lift unit includes means defining container abutment surfaces only adjacent the lower end thereof for allowing movement of the containers through said openings only after the container has been raised a predetermined amount above the fork lift tines. 